Does the awesomeness of cats allow them to violate the laws of physics?
February 13, 2015 8:13 AM   Subscribe

I’d like to get a better understanding (or, really, any understanding) of how cats are able to survive under extremes of temperature.

I have house cats that enjoy lying right across heating vents in my floor, where they are blasted by hot air from the furnace. From what I understand, cats evolved from desert-dwelling ancestors, so perhaps their love for heat isn’t as mysterious as their ability to survive in extreme cold. I maintain two colonies of feral cats that are currently enduring sub-zero (Fahrenheit) temperatures. How do they do it?

Frankly, I don’t get it. I know cats are wonderful creatures, but they have to obey the laws of physics, just like everyone else. If you look at the tips of their ears, they don’t have a lot of fur covering them, and the flesh is thin. Why don’t these tips freeze-off as soon as the temperature drops? It’s true that I’ve seen a handful of feral cats that were, in fact, missing their ear tips, but the majority of ferals don’t have any obvious problems with frostbite, either on their ears or their other extremities. This fact is quite amazing and puzzling to me.

I’ve tried doing some Google searches about temperature regulation in cats, but the results are not very interesting: Just a bunch of handy-wavy generalities. I don’t know exactly what sorts of answers I’m looking for, but maybe something about how they can ramp-up (or ramp-down) their metabolic rate, or the insulating properties of their fur, or antifreeze proteins in their plasma, or some such thing.

Maybe my question is too specific, so if there is information about other (non-feline) animals who can endure extremes in temperature, I’d be interested in that, as well.
posted by akk2014 to Pets & Animals (8 answers total) 5 users marked this as a favorite
Just to address your last paragraph: watching birdfeeders in the winter is fascinating. My titmice looked twice as big as usual, because their feathers were really thick and puffed up. The first time I saw them that way, I thought they'd swallowed a mouse or something.
posted by Melismata at 8:20 AM on February 13, 2015

As for the frostbite thing--the cats you see are the ones that are reasonably healthy, getting food, and finding warm(ish) places to hunker down when it's really cold.

The frostbitten ones are hiding because they're injured and dying from infections and such so you see them less often. Occasionally one makes it through so you see them with ear tips or whatever missing.
posted by sevenless at 8:27 AM on February 13, 2015 [4 favorites]

I can't address cats specifically, but animals that live in temperature extremes generally have some kind of circulatory system adaptation which keeps warm blood moving through their extremities. Birds, for example, have specialized capillaries in their legs which keep them from like freezing and snapping off (I mean come on, have you seen bird legs? They are like twigs). Incidentally, similar adaptations are useful in warm weather, allowing the extremities to act as radiators, dissipating extra heat into the relatively cooler environment, e.g. elephant ears. There are probably also metabolic adaptations (like greater amounts of brown fat) allowing more efficient conversion of calories to warmth, but I'm also hand-waving here--I don't actually know if cats have it.

Humans don't have these circulatory system adaptations, and when we're cold we constrict the capillaries in our extremities. This keeps more warm blood in our core, preventing hypothermia, but has the unfortunate knock-on effect of making it relatively easy for the skin containing these constricted capillaries to freeze, since its supply of warm blood has been cut off. If you think about it, humans are the "desert" (or at least warmth-adapted) species here: no fur, no specialized adaptations to allow us to go outside naked when it's even moderately cold.

For what it's worth, I also think feral cats often lose their ear tips to frostbite, but it's tough to tell because many shelters dock the ears of strays as part of the spay/neuter procedure, with the idea that it will allow you to tell if a cat has been sterilized from a safe distance.
posted by pullayup at 8:35 AM on February 13, 2015 [4 favorites]

Yes, you are unfortunately wrong about cat ears not getting frostbite. But cat ears do play a role in thermoregulation. In your googling you probably want to search desert mammal thermoregulation.
posted by zennie at 8:35 AM on February 13, 2015

Winter World: The Ingenuity of Animal Survival is an entire, well-written and totally engrossing book on this subject. Did you know that some caterpillars make their own glycerol (anti-freeze) to make it through the winter?
posted by charmedimsure at 8:43 AM on February 13, 2015 [8 favorites]

Keep in mind that, unlike humans, feral cats aren't dumb.

Humans get frostbite because they're stupid enough to go outside -- unprepared -- when its cold enough to cause frostbite. Frostbite doesn't often surprise you. Or, at least, it shouldn't.

If it's extremely cold outside, feral cats (and most other wild animals) will find a place to hunker down, and they will stay there as long as it takes, as long as they can. In these conditions, there's absolutely nothing else on their minds beyond food, water and shelter. They're not taking risks. They're not summiting Everest.

Animals have a different definition of "quality of life" than we do.
posted by Cool Papa Bell at 9:15 AM on February 13, 2015 [9 favorites]

I would also guess that a big part of "hunkering down" in extreme cold involves much curling up. It would be pretty hard to get frostbite with your nose and ears wrapped up under your coat. And since cats can happily sleep curled in one spot indefinitely (or so it seems from my observations), hunkering down isn't a big deal for them. If you asked us to hunker down in a box or dead tree, we might make it through the night, but eventually we'd be all, "screw this, I've got to build an igloo or something--hell, I'll take my chances wandering in the blizzard so long as I get out of this bullshit!"
posted by gueneverey at 9:52 AM on February 13, 2015 [1 favorite]

That behavior of seeking the heat of your furnace vents is part of it too. Fairly recently a greyhound in the suburbs around here got out of her owner's yard during a time of really, really cold temperatures. Now greyhounds are way back in history also a desert animal, and they have thin coats with no undercoat and like zero body fat. Not exactly optimized for survival in the Chicago winter. After two nights gone (maybe more?) we all assumed this girl was lost for good.

But she was found, and here's the ticket: when she turned up, she was really dirty and smelled distinctly like chicken shit. Apparently she found a chicken coop and hunkered down with them in the relative warmth.

Animals have pretty great survival instincts that aren't hampered by panic, emotions, or attempts at "logic" like humans.
posted by misskaz at 12:05 PM on February 13, 2015

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